Flow distribution pad and methods for using them

ABSTRACT

Apparatus and methods are provided for delivering fluids into a patient&#39;s body that includes a tubular member including a proximal end, a distal end sized for introduction into a patient&#39;s body, and a fluid delivery lumen extending between the proximal and distal ends; and a flexible pad on the distal end including a tissue contacting surface, a passage communicating with the fluid delivery lumen, and plurality of capillary channels in the tissue contact surface communicating with the passage, the capillary channels configured to deliver fluid from the fluid delivery lumen and passage to tissue contacted by the tissue contact surface.

RELATED APPLICATION DATA

This application is a continuation of co-pending application Ser. No.15/439,922, filed Feb. 22, 2017, issuing as U.S. Pat. No. 11,583,667,which claims benefit of provisional application Ser. No. 62/298,455,filed Feb. 22, 2016, the entire disclosures of which are expresslyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to apparatus, systems, andmethods for delivering fluids into a patient's body, and moreparticularly to apparatus, systems, and methods for deliveringrelatively low volumes of fluids to tissue or other body surfaces.

BACKGROUND

Topical medications and other liquids are frequently applied usingabsorbent swabs, pads, and/or sponges. Even for single applications,this can be a wasteful and/or imprecise method of agent delivery. Inapplications where continuous or repeated agent delivery is desired,this becomes even more problematic since, ideally, the flow rate forcontinuous application would be quite small but there is a need forconsistent delivery and/or diffusion over a larger surface.

Therefore, apparatus and methods that facilitate delivering agents orfluids in a controlled manner would be useful.

SUMMARY

The present invention is directed to apparatus, systems, and methods fordelivering fluids into a patient's body, and more particularly toapparatus, systems, and methods for delivering relatively low volumes offluids to tissue or other body surfaces.

In accordance with one embodiment, an apparatus is provided fordelivering fluids into a patient's body that includes a tubular membercomprising a proximal end, a distal end sized for introduction into apatient's body, and a fluid delivery lumen extending between theproximal and distal ends; and a flexible pad on the distal end includinga front or tissue contact surface, a passage communicating with thefluid delivery lumen, and plurality of capillary channels in the tissuecontact surface communicating with the passage, the capillary channelsconfigured to deliver fluid from the fluid delivery lumen and passage totissue contacted by the tissue contact surface.

In accordance with another embodiment, a system is provided fordelivering fluids into a patient's body that includes a tubular membercomprising a proximal end, a distal end sized for introduction into apatient's body, and a fluid delivery lumen extending between theproximal and distal ends; a flexible pad on the distal end including atissue contact surface, a passage communicating with the fluid deliverylumen, and plurality of delivery channels in the tissue contact surfacecommunicating with the passage, the delivery channels configured todeliver fluid from the fluid delivery lumen and passage to tissuecontacted by the tissue contact surface; and a source of fluidconnectable to the proximal end of the tubular member for delivering thefluid through the fluid delivery lumen and along the delivery channels.

Optionally, the tubular member may include a vacuum lumen extendingbetween the proximal and distal ends, and wherein the pad includes oneor more vacuum ports in the front surface communicating with the vacuumlumen, the one or more vacuum ports being spaced apart from the deliverychannels, and the system may further include a source of vacuumconnectable to the proximal end of the tubular member for delivering avacuum through the vacuum lumen to the vacuum ports.

In accordance with still another embodiment, a method is provided fordelivering fluids into a patient's body that includes introducing a padincluding a tissue contact surface and plurality of delivery channels inthe tissue contact surface into a body passage; placing the tissuecontact surface against a body surface adjacent the body passage suchthat open sides of the delivery channels contact the body surface; anddelivering fluid into the pad such that the fluid flows along thedelivery channels to distribute the fluid over a portion of the bodysurface.

Other aspects and features of the present invention will become apparentfrom consideration of the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate exemplary embodiments of the invention, inwhich:

FIG. 1 is a side view of an exemplary embodiment of a fluid deliverydevice that includes a pad including recessed delivery channels fordelivering fluid to a surface contacted by the pad.

FIG. 2A is a detail of a pad that may be included in the delivery deviceof FIG. 1 .

FIG. 2B is a cross-section of the pad of FIG. 2A taken along plane2B-2B.

FIGS. 3A-3D are end views of a tissue contact surface that may beincluded in a pad of a delivery device, showing exemplary embodiments ofnetworks of delivery channels that may be provided in the tissue contactsurface.

FIG. 4A is a side of another exemplary embodiment of a fluid deliverydevice that includes a pad including recessed delivery channels fordelivering fluid to a surface contacted by the pad.

FIG. 4B is a view of a front surface of the pad of FIG. 4A.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Turning to the drawings, FIGS. 1-2B shows an exemplary embodiment of afluid delivery device 8 that includes an elongate catheter, shaft, orother tubular member 10 carrying a pad 20 including recessed deliverychannels 30 for delivering fluid to a surface contacted by the pad 20,e.g., a tissue or other body surface 90 of a patient. Generally, thecatheter 10 is an elongate tubular member including a proximal end 12, adistal end 14 sized for insertion into a patient's body, and one or morelumens 16 extending between the proximal and distal ends 12, 14, therebydefining a central longitudinal axis 18. For example, the catheter 10may include an infusion lumen 16 that extends between the proximal anddistal ends 12, 14, e.g., communicating with the delivery channels 30 inthe pad 20, as described further below. Optionally, the catheter 10 mayinclude one or more additional lumens, e.g., a vacuum lumen (not shown)to enhance securing the pad 20 to the body surface 90, as describedfurther elsewhere herein.

The catheter 10 may be substantially flexible, semi-rigid, and/or rigidalong its length, and may be formed from a variety of materials,including plastic, metal, and/or composite materials, as is well knownto those skilled in the art. For example, in one embodiment, thecatheter 10 may be semi-rigid or rigid at the proximal end 12 to enhancepushability and/or torqueability of the catheter 10 without substantialrisk of buckling or kinking. At the distal end, the catheter 10 may beflexible or semi-rigid, e.g., having sufficient column strength suchthat a distal force may be applied to the pad 20 from the proximal end12, but may have some flexibility to accommodate insertion into anirregular passage, such as a patient's mouth, throat, gastrointestinaltract, and/or airway or through a port into a patient's thoracic cavity,abdomen and the like (not shown). Alternatively, the device may beplaced or implanted sub-dermally, epidurally, or in other locationswithin the body. Further, Alternatively, the catheter 10 may besubstantially flexible along its entire length or at least for apredetermined distance from the distal end 14 to facilitate advancementthrough one or more longer body passages, e.g., within a patient'svasculature. In another alternative, the catheter 10 may be malleablesuch that the catheter 10 may be bent to a desired shape when apredetermined threshold force is exceeded, which may be maintained untilbent further, e.g., such that the catheter 10 may be arranged into adesired geometry based on the patient anatomy involved.

In an exemplary embodiment, the catheter 10 may include an inner linerat least partially or entirely surrounding or otherwise defining theinfusion lumen 16, a reinforcement layer surrounding the inner liner,and an outer jacket surrounding the reinforcement layer (not shown),each of which may extend at least partially between the proximal anddistal ends 12, 14 of the catheter 10. Optionally, the infusion lumen 16may include lubricious material or may be formed from one or more layersof thermoplastic or other polymeric material including one or morecoatings on the inner surface having desired properties, e.g., ahydrophilic and/or lubricious coating.

Returning to FIG. 1 , a handle or hub 50 may be provided on the proximalend 12 of the catheter 10, e.g., configured and/or sized for holdingand/or manipulating the device 8 from the proximal end 12. In addition,the handle 50 may include one or more ports, e.g., port 52 communicatingwith the infusion lumen 16, which may be coupled to a source of fluid,e.g., a syringe, container, and/or fluid line (not shown), as describedfurther elsewhere herein. Optionally, the port 52 may include one ormore valves or connectors, e.g., a Luer fitting, for removablyconnecting the source of fluid to the port 52.

With particular reference to FIGS. 2A and 2B, the pad 20 may be agenerally planar or disc member including a front or tissue contactsurface 22, a back surface 24 including a hub 26 or other feature forattaching the pad 20 to the distal end 14 of the catheter 10, and anouter perimeter 25 extending between the front and back surfaces 24, 26.In exemplary embodiments, the hub 26 may be coupled to the distal end 14by one or more of an interference fit, e.g., by receiving one of thedistal end 14 and the hub 26 in a recess in the other of the hub 26 andthe distal end 14, by bonding with adhesive, fusing, sonic welding,insert molding, over-molding, and the like. The pad 20 also includes apassage 28 extending between the hub 26 and the front surface 22, e.g.,communicating with the lumen 16 for delivering fluid from the lumen 16to delivery channels 30 in the front surface 22.

As best seen in FIG. 2B, the delivery channels 30 may include aplurality of recesses formed in the front surface 22, e.g., having adesired cross-sectional shape to facilitate capillary action directingfluid along the delivery channels 30. For example, as shown in FIG. 2B,the delivery channels 30 may have a “U” shaped cross-section, e.g., witha rounded bottom wall 32, substantially vertical, straight side walls34, and an open side 36 along the front surface 22. Alternatively, thedelivery channels 30 may have other shapes, e.g., a “V” shapedcross-section, a partial circular or elliptical cross-section, e.g.,such that the side walls define a generally circular or other curvedarc, e.g., less than or greater than one hundred eighty degrees (180°)of a circle, or other cross-section. The delivery channels 30 may have asubstantially uniform cross-sectional width, e.g., between the sidewalls 34, and/or depth, e.g., between the bottom wall 32 and the openside 36, e.g., having a maximum cross-sectional width or depth of notmore than one or two millimeters (1.0-2.0 mm). Alternatively, the widthand/or depth may be varied in different regions of the front surface 22,e.g., to promote fluid flow in a desired manner along the front surface22.

The pad 20 may be substantially rigid, semi-rigid, or flexible, asdesired, e.g., formed from plastic, metal or composite materials. Forexample, the pad 20 including the hub 26 may integrally formed, e.g.,molded, cast, and the like, from PEBAX, urethane, silicone, or othermaterial. Optionally, the pad 20 may be formed at least partially fromhydrophilic and/or lubricious material, e.g., over the front surface 22,which may enhance capillary action delivering fluid along the deliverychannels 30. In another option, at least the walls of the deliverychannels 30 may be coated with hydrophilic and/or lubricious material.

In one embodiment, the pad 20 may be formed from conformable materialthat maintains a predetermined shape when free from external forces, yetallows the front surface 22 to conform to contacted tissue, e.g., when adistal force is applied from the proximal end 12 of the catheter 10, asdescribed elsewhere herein. The flexibility of the pad 20 may besubstantially uniform along the front surface 22 or may be different indifferent regions, e.g., more rigid in the center, e.g., around the hub26, and more flexible away from the hub 26, e.g., towards the outerperimeter 25. In an exemplary embodiment, the front surface 22 of thepad may be biased to one of a substantially flat, concave, or convexshape, which may be deformed when pressed against a contacted surface,e.g., to place the front surface 22 firmly against the contacted surfacesuch that the delivery channels 30 are sealingly placed against thecontacted surface, e.g., such that the contacted surface substantiallyseals the open end 36 of the delivery channels 30.

For example, in a relaxed state, the pad 20 may have a shallow cupshape, i.e., such that the front surface 22 has a shallow concave shapewith a lip or rim (not shown) extending around the perimeter 25 adjacentthe front surface 22. In one embodiment, the lip may define an outerchannel (not shown) on the front surface 22 of the pad 20.Alternatively, one or more projections or features (not shown) may beprovided on the pad 22 within the lip to divide the channel into smallerchannels and/or prevent the channel from collapsing when the frontsurface 22 of the pad 20 is pressed against tissue. When the frontsurface 22 is pressed against a contacted surface, the lip may provide aseal around the perimeter 25, while the front surface 22 deforms to sealone or more of the delivery channels 30 against the contacted surface.In this manner, fluid introduced through the lumen 16 and passage 28 mayreach the delivery channels 30 and spread along the delivery channels 30outwardly towards the perimeter 25 of the pad 20, e.g., thereby applyingthe fluid and any agents therein to tissue of the contacted surface.

For example, as shown in FIG. 2A, the passage 28 includes an opening 28a at the front surface 22 and the delivery channels 30 may extendlaterally and/or outwardly from the opening 28 a. A relatively smallvolume of fluid may be introduced through the lumen 16 into the passage28 such that the fluid pools at the opening 28 a against the contactedsurface. The fluid may then travel out into the delivery channels 30along the contacted surface towards the perimeter 25 of the pad 30 todistribute the fluid over the contacted surface, where the fluid may beabsorbed or otherwise delivered to tissue at or beneath the contactedsurface.

In an exemplary embodiment, the fluid may include a topical anestheticor other agent, which may be absorbed by the tissue, e.g., to expose theanesthetic to nerves adjacent the tissue. For example, the pad 20 may beplaced in contact with the patient's skin or a mucosal surface,whereupon the anesthetic may be delivered to the front surface 22 andspread out along the delivery channels 30 and be absorbed by the tissue,e.g., to block the underlying nerves. In exemplary embodiments, arelatively small volume of fluid may be delivered, e.g., between aboutone to five milliliters (1.0-5.0 mL), which may be sufficient to flowout through the delivery channels 30 to deliver sufficient dosage ofanesthetic or other agent to the tissue. Optionally, a procedure may beperformed at or adjacent the contacted tissue, e.g., after removing thepad 20 or while the agent is intermittently or continuously introducedthrough the lumen 16 to the delivery channels 30. Once sufficient fluidhas been delivered or the procedure is completed, the device 8 may beremoved.

Turning to FIG. 3A, an exemplary embodiment of a network of deliverychannels 30 is shown. In this embodiment, the front surface 22 of thepad has an elliptical or other oblong shape around the perimeter 25,i.e., with a length greater than its width. In an exemplary embodiment,the pad 20 may have a width between about two and thirty millimeters(2.0-30 mm), e.g., about 0.2 inch (5.0 mm), and a length between aboutten and fifty millimeters (10-50 mm), e.g., approximately one inch (25.0mm). Alternatively, the front surface 22 may have other shapes, e.g., asubstantially circular shape, a rounded square or rectangular shape, andthe like. In addition, as shown, the delivery channels 30 may bearranged to include a plurality of radial channels 32 that communicatewith the opening 28 a and extend outwardly away from the opening 28 atowards the perimeter 25, and a plurality of circumferential channels 34that communicate with the radial channels 32 and extendcircumferentially, e.g., in circular or oblong paths concentric to theouter perimeter 25, to distribute fluid from the opening 28 a throughthe radial and circumferential channels 32, 34 over a portion of thefront surface 22. In this manner, fluid delivered to the opening 28 amay travel outwardly by capillary action through the radial channels 32and the circumferential channels 34 to distribute the fluid over and/orinto tissue at the contacted surface.

Alternatively, as shown in FIG. 3B, a pad 20′ is shown that includes apair of openings 28 a′ spaced apart from one another on the frontsurface 22.′ For example, a single passage (not shown) may extend fromthe hub (also not shown) of the pad 20′ and divide to communicate withboth openings 28 a.′ Each opening 28 a′ may include a network ofdelivery channels 30′ including radial channels 32′ and circumferentialchannels 34′. As shown, the network of channels 30′ from each opening 28a′ may interconnect and/or otherwise communicate with each other, whichmay enhance distribution of fluid over the front surface 22.′Alternatively, each opening 28 a′ may include an independent network ofdelivery channels (not shown), e.g., isolated from the other network,for delivering fluid along respective regions of the front surface 22.′In this embodiment, the front surface 22′ has an oblong shape, as shown,although the front surface 22′ may have other shapes, as desired.Although two openings 28 a′ are shown in FIG. 3B, it will be appreciatedthat any desired number of openings and corresponding networks ofdelivery channels may be provided on the pad.

In another alternative, shown in FIG. 3C, a pad 20″ is shown thatincludes a network of channels 30″ including radial channels 32″ thatextend orthogonal to one another outwardly towards the perimeter 25,″e.g., vertically and horizontally from the opening 28 a,″ and lateralchannels 34″ that extend orthogonally from the radial channels 32.″ Instill another alternative, shown in FIG. 3D, another pad 20′″ is shownthat includes a network of delivery channels 30′″ that extend outwardlyfrom an opening 28 a′″ in a random pattern, e.g., including a pluralityof channels 30′″ that extend at least partially radially andcircumferentially outwardly towards the perimeter 22′″.

Turning to FIGS. 4A and 4B, another embodiment of a fluid deliverydevice 108 is shown that includes an elongate catheter, shaft, ortubular member 110 carrying a pad 120 including recessed deliverychannels 130 in a front surface 122 thereof for delivering fluid to asurface contacted by the pad 120, generally similar to the previousembodiment. The catheter 110 also includes an infusion lumen 116 acommunicating between a first port 152 a in the handle 150 (connectableto a source of fluid 60) and a passage 128 extending from a hub 126 on afirst end 120 a of the pad 120 to an opening 128 a in the front surface122 that communicates with the delivery channels 130, also similar tothe previous embodiment, such that the delivery channels 130 extendpartially between the first end 120 a and a second opposite end 120 b ofthe pad 120 without extending entirely to the second end 120 b. Inaddition to the infusion lumen 116 a, the catheter 110 also includes asecond lumen 116 b extending between the proximal and distal ends 112,114 of the catheter 110, e.g., from a second port 152 b in the handle150 to a second passage 129 in the hub 126 and pad 120.

The second port 152 b may be coupled to a source of vacuum, e.g., asyringe, vacuum line, and the like 62 for enhancing engagement of thefront surface 122 with a tissue or other contacted surface (not shown).For example, the second passage 129 may communicate with one or morevacuum ports 129 a in the front surface 122, e.g., a plurality of vacuumports 129 a spaced apart around the front surface, that aresubstantially spaced apart or otherwise isolated from the deliverychannels 130. Thus, when the front surface 122 is pressed against acontacted surface and a vacuum is applied to the second lumen 116 b andpassage 129, the vacuum may be applied to the vacuum ports 129 a,thereby engaging the front surface 122 against the contacted surface.Fluid may then be delivered via the delivery channels 130, similar tothe previous embodiment, to distribute the fluid over the contactedsurface and/or into tissue underlying the contacted surface.

Such vacuum ports 129 a in the front surface 122 may be particularlyuseful if the pad hub 126 extends from the perimeter 125 of the pad 120,rather from the back surface 124, since a distal force applied from theproximal end 112 of the catheter 110 may not be effective in pressingthe front surface 122 against a desired surface. Optionally, theflexibility of the pad 120 may be varied over the front surface 122,e.g., more rigid on the end 120 a closer to the hub 126 and moreflexible on the opposite end 120 b. In this option, the vacuum ports 129a may allow the flexible region to be pulled against and/or conform to atissue surface, which may enhance delivery of fluid to the tissue.

During use, the device 8 or 108 may be introduced into a body passage todirect the front surface 22, 122 of the pad 20, 120 against a targettissue or bodily surface to allow a relatively small volume of fluid tobe delivered and/or to allow fluid to be delivered slowly, e.g.,intermittently or substantially continuously, in order to treat thetissue and/or to prepare the tissue for a subsequent procedure, e.g., adiagnostic and/or therapeutic procedure. During introduction, the pad20, 120 may remain in its relaxed, e.g., generally planar or concave,orientation, if the bodily passage is sized to accommodate the pad 20,120.

Alternatively, the pad 20, 120 may be compressed, e.g., rolled orfolded, into a contracted state to facilitate introduction into asmaller bodily passage. For example, an introducer sheath or othertubular body (not shown) may be provided that is sized to be introducedinto a target region that includes a lumen therein. The pad 20, 120, inits contracted state, may be sized to be received within the lumen ofthe introducer sheath and advanced therethrough into the target region,whereupon the pad 20, 120 may be deployed. Once deployed, the pad 20,120 may assume its original orientation, and the front surface 22, 122may be directed towards a desired surface at the target region and fluidmay be introduced, similar to the methods described above.

The foregoing disclosure of the exemplary embodiments has been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Many variations and modifications of the embodiments described hereinwill be apparent to one of ordinary skill in the art in light of theabove disclosure.

Further, in describing representative embodiments, the specification mayhave presented the method and/or process as a particular sequence ofsteps. However, to the extent that the method or process does not relyon the particular order of steps set forth herein, the method or processshould not be limited to the particular sequence of steps described. Asone of ordinary skill in the art would appreciate, other sequences ofsteps may be possible. Therefore, the particular order of the steps setforth in the specification should not be construed as limitations on theclaims.

While the invention is susceptible to various modifications, andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is not to be limited to the particular formsor methods disclosed, but to the contrary, the invention is to cover allmodifications, equivalents and alternatives falling within the scope ofthe appended claims.

1. An apparatus for delivering fluids into a patient's body, comprising:a tubular member comprising a proximal end, a distal end sized forintroduction into a patient's body, and a fluid delivery lumen extendingbetween the proximal and distal ends; and a flexible pad on the distalend including a tissue contact surface, a passage communicating with thefluid delivery lumen, and plurality of delivery channels in the tissuecontact surface communicating with the passage, the delivery channelsconfigured to deliver fluid from the fluid delivery lumen and passage totissue contacted by the tissue contact surface.
 2. The apparatus ofclaim 1, wherein the delivery channels comprise a plurality of recessesformed in the tissue contact surface.
 3. The apparatus of claim 2,wherein the recesses have one of a “U” and “V” shaped cross-section. 4.The apparatus of claim 2, wherein the recesses have a maximumcross-sectional width of not more than 0.5 to two millimeters such thatfluid flows along the recesses by capillary action.
 5. The apparatus ofclaim 1, wherein the passage includes an opening at the tissue contactsurface and wherein the delivery channels extend outwardly away from theopening along the tissue contact surface towards an outer periphery ofthe pad to distribute fluid from the opening along the delivery channelsover a portion of the tissue contact surface.
 6. The apparatus of claim5, wherein the delivery channels include a plurality of radial channelsthat communicate with the opening and extend outwardly away from theopening and a plurality of circumferential channels that communicatewith the radial channels to distribute fluid by capillary action fromthe opening through the radial and circumferential channels over aportion of the tissue contact surface.
 7. The apparatus of claim 5,wherein the delivery channels include a plurality of radial channelsthat communicate with the opening and extend outwardly away from theopening and a plurality of lateral channels that communicate with theradial channels to distribute fluid from the opening by capillary actionthrough the radial and lateral channels over a portion of the tissuecontact surface.
 8. The apparatus of claim 1, wherein the passagecommunicates with a plurality of openings at the tissue contact surfaceand wherein the delivery channels extend outwardly away from theopenings along the tissue contact surface towards an outer periphery ofthe pad to distribute fluid from the openings along the deliverychannels over a portion of the tissue contact surface.
 9. The apparatusof claim 1, wherein the pad is formed from conformable material thatallows the tissue contact surface to conform to contacted tissue. 10.The apparatus of claim 9, wherein the tissue contact surface is biasedto one of a substantially flat, concave, or convex shape.
 11. Theapparatus of claim 1, wherein the passage includes first and second ofopenings spaced apart from one another at the tissue contact surface,and wherein the delivery channels including first and second networks ofchannels extending outwardly away from the respective openings along thetissue contact surface to distribute fluid from the openings along thedelivery channels over a portion of the tissue contact surface.
 12. Theapparatus of claim 1, wherein the tubular member further comprises avacuum lumen extending between the proximal and distal ends, and whereinthe pad includes one or more vacuum ports in the front surfacecommunicating with the vacuum lumen, the one or more vacuum ports beingspaced apart from the delivery channels.
 13. The apparatus of claim 1,wherein the pad has an outer perimeter extending between the frontsurface and a back surface of the pad. 14-20. (canceled)
 21. A methodfor delivering fluids into a patient's body, comprising: introducing apad including a tissue contact surface and plurality of deliverychannels in the tissue contact surface into a body passage; placing thetissue contact surface against a body surface adjacent the body passagesuch that open sides of the delivery channels contact the body surface;and delivering fluid into the pad such that the fluid flows along thedelivery channels to distribute the fluid over a portion of the bodysurface.
 22. The method of claim 21, wherein the delivery channels aresized such that the fluid flows along the delivery channels by capillaryaction.
 24. The method of claim 21, wherein the body passage is anairway.
 25. The method of claim 21, wherein the pad is provided on adistal end of a tubular member, and wherein introducing the padcomprises introducing the distal end of the tubular member into the bodypassage.
 26. The method of claim 21, wherein delivering fluid comprisesintroducing the fluid through a lumen of the tubular member through apassage in the pad to the delivery channels.